Thank you. I don't see Java as having a performance edge over Python ))

Same for the other languages - they likely won't have the performance of C++ or Rust. But I'll test them anyway, even just for the academic exercise the endeavour is worthwhile. Thank you.

Java is about an order of magnitude faster than Python. It's a JIT-compiled statically typed language, after all, and Oracle's JIT compiler is the best in class.

That said, given your original request, I don't think it has much to do with language choice. Displaying a very large number of rows in a data grid or similar is a classic GUI task in line-of-business apps, and the answer has always been either virtualization (lazy loading) or pagination.

One trick to improve UX when virtualizing data is to do preloading asynchronously in the background - ideally on a separate thread - and start it before the user scrolls all the way to the end (e.g. when there's still a couple of pages of data left).

Yes, that is exactly what I have been doing. Thank you.

One thing that I would like to discover is how to adjust the scroll bar size so that it appears as if more records are loaded than actually are.

In Qt you should use the model/view framework if possible. It gives a virtualized list with a render callback. https://doc.qt.io/qtforpython-6/overviews/qtwidgets-model-vi...

Thank you. I will definitely peruse this.

Java is actually pretty fast, and certainly much, much faster than python. There are plenty of reasons Java isn't my preferred language, but speed is not one of them.

This is great to know, thank you. I still remember the days of the knock, knock jokes about Java.

The jokes were mostly about startup time for the JVM (only happens once as when its in RAM it stays there and the loading time doesn't repeat for the next java program you run). It was also a lot more notable in the 90s when java was a browser plugin to run applets and browsers were single threaded (so the browser froze for a few seconds while the JVM loaded).

I think it's been out of date for a long time with modern computers having much more RAM and speedy SSDs (and also JVM optimizations). For actual run time performance once its loaded the JVM has had great performance in the early 00s already and improved since. And for server side it was never an issue as you don't restart the server very often (so the JVM is always already loaded).

Thank you, I will evaluate Java for this purpose, though I almost certainly won't actually use it in the rewrite.